Gas package



G. C. QUELCH May 9, 1933.

GAS PACKAGE Filed Nov. 10, 1928 QOMPRESSED BAS 1 R|Ev comPRESSED STABLESAS INVENToR feo/yea @Heidi BY MM M. ATTORNEY PGI-ASH" Patented May 9,1933 UNITE TES ATENT FICE GEORGE C. QUELCH, OF OAKMONT, PENNSYLVANIA,ASSIGNOR, BY MESNE ASSIGN- MENTS, TO UNION CAR-EIDE AND CARBON RESEARCHLABORATORIES, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK GASPACKAGE Application filed November 10, 1928.

My present invention relatos to making natural gas suitable for use Withoxygen in a blow torch to preheat and cut metal and at the same timesuitable for storage in tanks at very high pressure yet capable of usewith standard reducing valves and regulating equipment. It must be freefrom Water or paraiiin vapors when stored in the pressur@J container andshould be suitable When compressed to 2,000 pounds per square inch forstorage purposes. Its B. t. u. content shouldI be as high as ispracticable for free gas and its flame temperature high enough to eliecteiicient preheating of metal.

Natural gas as it comes from the mains, if compressed to 2,000 poundsper square inch would fail to meet these requirements because of theconsiderable amount of Water gas and paraiiu vapor which it carries andwhich would cause freezing and gumming at the valves when the gas isexpanded through standard regulating apparatus.

By my present invention, I provide a means for and a method of treatingnatural gas which will not only free it from the undesirable parain andWater vapors but which Will permit the retention of all unobjectionablehomologues in order that losses 1n the B. t. u. content of the gas maybe avoided.

The apparatus used is extremely simple and the method may beasubstantially continuous one which takes the natural as directfrom themains, compresses 1t and charges it at the desired pressure directlyinto the pressure containers with most of the undesirable Water andpara-ilin vapors removed.

An important feature of the invention and one which greatly simplifiesthe apparatus and speeds up the method is the use of drying agents inthe compressed gas containers so that the nal drying occurs in thecontainers after the gas has been packaged ready for shipment.

Practically all of the natural gas distributed in the Pittsburghdistrict has been treated at relatively low pressures for the 'recoveryof certain readily condensible fractions. The gas analysis after suchtreatment Serial N0. 318,413.

varies somewhat at different plants but may be said to contain thcfollowing elements` at close to the general proportions listed:

Methane 84.7 to 87.4 Ethane 6.8 to 9.4 Propane 1.55 to 3.0 Butane 1.81to 1.3 Pentane trace Nitrogen 1.6 to 3.2 Oxygen trace to .1

rIhe Water vapor content is around 2%, the iame temperature around`4200D F. and the B. t. u; per cubic foot in the neighborhood of 1125 to1150.

If a gas having the above approximate analysis is compressed to 2,000pounds per square inch and then expanded through the ordinary reducingvalve, there Will be trouble at the valve. The Water vapor will freezeand the parailin vapor Will liquefv at the valve and the valve openingwould be quickly completely blocked or rendered totally ineicient foreffecting a continuous and regulable supply of gas. The compressed gasmixture would be unstable.

Part of the Water vapor and part ofthe condensible paraffin vapors canbe removed by compression and subsequent cooling the natural gas fromthe mains, this removal being assisted by the aifinity of certain 'ofthe oil vapors for the lubricating oil .used in the compressors. rIhecondensed vapors may betrapped and drawn off With the Water vaporscompressed out of the gas. Such a method, however, even whensupplemented by the passage of the gas through chemical drying means isnot suiiicientl'y eifective When carried out at commercially practicablepressures, say above 1500 pounds per-square inch to give a product whichis usablewhen subsequently stored at 2,000 pounds.

In accordance with the present invention, therefore, I supplement thecompressing, cooling and chemical drying method of gas treatment by afinal chemical drying which occurs in the compressed gas container.Preferably this final drying is accomplished by the provision of a smallquantity of caus-l tic potash in the gas container, such potash beingpreferably of Walnut size so that it may be readily introduced throughthe ordinary 5% inch valve opening in the container. I ind that afterthe gas has been partially dried by the successive steps of compression,cooling and chemically drying and then introduced into a tank containingthe caustic potash at the pressure of 2,000 pounds per square inch,final drying Will occur in 24 hours producing a stable gas Which issufficiently dry to be expanded through a nozzle and which has thecalorific qualities necessary to produce the intense heat required for acutting flame.

A peculiarity of the final drying medium, to-Wit, the caustic potashused in the pressure tanks, is the fact that a single small charge ofsuch material, say about two pounds of it, will last for'years. Eventhough the tank which contains it be repeatedly Charged vvith gas, thepotash retains its drying efliciency over "unexpectedly long periods oftime.

From the foregoing general discussion of the invention, it `Will beuseen that one feature of my invention concerns a gas package consist-ingof a' gas at high pressure packaged in a pressure tank in the presence oa drying agent.

The invention from another aspect is concerned with a method andapparatus for treating natural gas to produce a suitable gas for storageat high pressures and which gas when mixed With oxygen Will-produce aneiicient cutting flame.

The invention may be more fully understood from the followingdescription in connection with the accompanying drawing which is adiagrammatic lvievv showing the apparatus which carries out the processby taking natural gas from the mains and charging it in a highlycompressed and part-ially' dried conditionintov a final gas package.

In this draWing-I'have used the reference numeral to designate a conduitadapted to deliver natural gas from the main to a triple stagecompressor 11, 12 and 13 which compresses the gas to say about 1500pounds per square inch, certain of the Water vapors in the' gas beingliquefied and certain of the oil vapors being entrapped by thelubricating oils of the compressors. The highly compressed gas from thelast compressor 13 containing a certain amount of condensate is then'passed through a cooler 14 in which further condensation occurs. Waterinlets and outlets for the cooler are shown at 14a, 1&5. From the coolerthe gas and its entrainedv condensate pass through -a pipe 15 intoa-pinging bottle 16, the lower end of-Whieh is equipped with a valve 18tlgough whichcondensate maybe drained o Gas passes oil' :from the top ofthe pinger througl'i a pipe 21, which pipe delivers it into a stand-pipe22. The upper end of: the pipe 22 discharges into the first of a pair ofsimilar drying bottles or towers 23 adapted to contain a chemicaldryingl agei'it, while the lower end oi" the pipe 22 is equipped. With asecond drain valve 24 through which further condensate may be removed.The chemical drying agent used in the bottle 23 is preferably causticpotash 24, this pot-ash being approximately nut-size and being supportedin conventional manner upon a screen. 2 5 Within the bottle. The bottle23 may be surrounded by refrigcrating coils or other cooling jackets ifdesired. From the top of the drying bottle gas passes to the secondsimilar bottle7 thence through a pipe line 26 to a header l1 from whichthe tanks 27 are filled. A' header outlet pipe 42 is coupled directly tothe inlet valve boss 28 oi' the container. A valve 25ct is located inthe line 2G; When the process is started valve 26a is closed until thecompressor builds up a pressure of 1500 pounds in the system as shown bygauge 262). The Valve is then opened Wide enough to permit thecompressor to force gas into the cylinder 27 at its rated capacity untilthe pressure therein reaches 2,000 pounds. At this time by closing thevalve on one cylinder and opening the valve of the next one, gas is.directed into the second cylinder.

Prior to the application of the valve fitting 29 to the container 2",small amount of caustic potash 30 has been introduced into the bottom ofthe container through the valve opening 31. A couple ci. pounds ofpotash are ordinarily suilicicnt for the ordinary size tank. The potashis preferably of nut size so that it may be conveniently .introducedthrough the usual 3,4 inch valve opening 31.

Exactly what reactions occur in the. -various stages of the process havenot been ac. curately determined. I do know, however, that thecondensate which is tapped 'poil through the valve 18 consists ofcondensed Water vapors and condensed paraiiin-vapors mixed with a slightamount of the lubrieating .oil which has been carriedalong from thecompressor. Apparently themostv eilicient condenser temperature isapproximately 40" to 504 F. y

I alsov have discovered that gas passed through ali-apparatus suchasthat described above at a pressure maintained at 1400 to 1500 pounds,or over, still contains an undesirable quantity .of water vaporand par.-a-iiin vapor when it enters the storage container, these constituentsbeing 'sufficiently high to cause freezing at the valve if the gas wereto he immediately expanded from the normal tank pressure, in the usualWay. Nevertheless, within 2.4 lhours from the in:

gno

troduction. of the gas into the container, the supplemental dryingeffected by the potash 30 seems to have substantially removed orrendered harmless such undesirable vapors and the is well suited forexpansion in the regulating apparatus, without danger of freezing orclogging. As noted above, a single small charge of the caustic potashdrier in the tank not only takes care of the first charge of gas butalso repeated recharges, remaining efl'ective over a period of two yearsor more. This action seems to be phenomenal and I can offer no entirelysatisfactory explanation of it.

I have found that even though the gas at 1500 pounds pressure or over ispassed through, a long series of drying towers containing causticpotash, drying is still incomplete, yet I am apparently able to obtainsubstantially complete drying by letting the gas stand for 24- hours at.2,000 pounds pressure in the presence of a small amount of causticpotash, whereas passing it through an indefinite series of drying towerscontaining the same material is insufficient to produce my remarkableresults.

This might lead to various theories, as, for instance, that the dryingaction of the potash is dependent not so much on the surface which isexposed to the gas, but upon the time of exposure. It is obviouslyiinpracticable to reduce the rate of gas flow through the apparatus tosuch an extent that the gas would remain stagnantly in contact with thedrying agent over a long period of time. Another possibility is that thepotash acts as a mechanical, molecular or chemical storage reservoir,taking care of the freezing constituents while the tank is at full 2,000pounds pressure and giving off some or all of them when the pressure hasfallen to a point where freezing temperatures are no longer produced bythe expanslon.

By using some of the drying agent in the container, both of thedifficulties are overcome either by complete drying or by the abovesuggested temporary storage of the freezing constituents.

I believe that the time factor and the pressure factor are bothimportant in so far as the complete dr ing is concerned, but it ispossible that i the gas direct from the nal drying tower were simplystored in a large reservoir in the presence of caustic potash, similareffects might eventually result, but it would take a very long time atthe low pressures which would be practical in a large reservoir.. Suchmethod would also be objectionable in that it would involve recompressngof the gas whereas the present process permits the gas from the mains tobe compressed and forced right through the a paratus and into the finalshipping containers.

I claim l. As a new article of manufacture, a package includin atransportable storage and service tank having an outlet valve fitting, agas within the tank divested of all but a relatively small percentage ofcondensible vapor such as paraffin, moist-ure and the like and underrelatively high compression and a relatively small amount. of solidchemical gas drying agent in the tank.

2. As a new article of manufacture, a package including a transportablestorageand service tank having an outlet valve fitting, a stable gaswithin the tank divested of all but a relatively small percentageof'condensible vapor such as paraffin, moisture and the like and under apressure of the order of 133 atmospheres and a relatively small amountof solid chemical gas drying agent in the tank.

3. As a new article of manufacture, a package including a transportablestorage and service tank having an outlet valve fitting, natural gashaving most of its moisture and paraffin content removed, said gas beingcharged into the tank divested of all but a relatively small percentageof condensible vapor such as paraffin, moisture and the like and underhigh pressure in the tank and a relatively small amount of solidchemical gas drying agent in the tank.

4. As a new article of manufacture, a package including a transportablestorage and service tank having an outlet valve f1tting, a stable gasWithin the tank divested of all but a relatively small percentage ofcondensible vapor such as parafiin, moisture and the like and under apressure of approximately 2000 pounds per square inch and a relativelysmall amount of solid chemical gas drying agent in the tank, thegasdrying agent comprising lump material of sufficiently small size forintroduction through the valve fitting opening.

5. As a new article of manufacture, a gas package including atransportable storage and service tank, a stable gas Within the tankdivested of all but a relatively small percentage of condensible vaporsuch as paraffin, moisture and the like and of a character which willproduce a cutting flame when mixed with oxygen, the gas being at apressure of approximately 2000 pounds per square inch and a relativelysmall quantity o-f caustic otash in the bottom of `the said service tan6. As a new article of manufacture, a gas package including a tank, astable gas within the tank divestedv of all but a relativelyl smallpercentage of condensible vapor such as parafiin, moisture and the likeand of a character which will produce a cutting flame when mixed withoxygen, the gas being at a pressure of approximately 2000 poundsl persquare inch and a relatively small quantty of caustic potash in thebottomz-f the ank,i-the p'otash being @of ,applfoxinaely Walnut szefso#that it may lbe :Conveniently introdilcedi-thmugh the -val've bt/ingopen- 5 ing of the tarkpr-inr `L0 the: application vf the :'vlve'Afitting.

'-Sgnekat Ve'ifmm,l inthel county of Allegheny, land; 'State fvzPennSylvania this 7th -iss er,y AND. 1928.

GEORGE o

